The Yard Guys

[Zach]

Originally Posted by smackdaddy

How many builders are still doing those these days?

Does it matter, with the plethora of used boats that are out there for the sailing?

Plus, how many thread participants own a boat that is currently in production?

Signed,

It's cold out side, and I've been enjoying red wine... Zach

[neilpride]

Originally Posted by avb3

You mean this:

It is not possible to relate the speed directly to grounding force and in any case this would be meaningless as a low speed impact on rock may be more damaging than a high speed impact on mud. The mechanics of impact of yachts with containers, berg-bits or whales defies simple analysis. Solid mechanics would need to be factored in - quite inappropriate for a simple standard. This is a crude deterministic approach to a probabilistic load case and should be treated with caution.

Notwithstanding this, to give a feel only for the effective decelerating force (applied at the
centre of gravity) implied by 0,8g (10m boat) or 1.1g (20m boat), assuming a constant impulse
approach, a boat travelling at the hull speed would stop in about 0.5 second (translation only).
The load applied at the keel would cause a bow down attitude of (very roughly) 0.5m at the
bow. This all seems to constitute a pretty severe load case. Please note again – very rough
figures.

It emerged from the validation that some boats, particularly those with no girders had little
hope of complying with this load case, without substantial local reinforcement.

It is important to recognise differences between the risk/consequences of impact loads on
ocean racing boats with those of typical recreational craft. Hence, it was felt sensible to have
a dual grounding load case approach; NORMAL and ENHANCED. Designers/builders could opt
for either.

A category A or B yacht need not necessarily be designed to impact Type II. It is for the
designer or builder to decide. Type II may be applicable to ocean-going racing yachts in
collision with floating objects, ice flows or marine creatures. For other category A or B craft
(while designed to the appropriate requirements in all other respects) such a load case may not
be appropriate. Whatever type is selected, the following note shall be included in the owner’s
[I]manual to the effect: ‘This boat has been designed to a Impact Type [II] (delete as necessary)
grounding scenario as defined in ISO-12215-9, where the craft is expected to be operating at
[low] [high] speed prior to the impact (delete as necessary). While compliance does not
guarantee that the boat will suffer no damage in such a grounding, the resistance of a boat
designed to Type II is normally expected to be substantially greater than that designed to
Type I’.

Yes,thanks..

[Polux]

Originally Posted by neilpride

This is very very interesting...

http://www.boatdesign.net/forums/att...tion-study.pdf

Why do you think it is interesting. It is just a 2009 paper regarding validation of ISO 12215-9 to be part of the RCD, regulating loads and specifying the scantlings of sailing craft appendages (read and keels rudders) on monohull sailing boats till 24m in length.

Several boats were provided for testing by several companies and you can see that many did not comply with the new demands. You can see all the the Industry lobby did not want those rules and scantlings to be mandatory.

Well they are, since 2012:

ISO 12215-9:2012 - Small craft -- Hull construction and scantlings -- Part 9: Sailing craft appendages

It means that new boats have to be modified to comply with the new more demanding rules, as it emerged from the validation process. They did not want to but were forced to. Boats will have to be more reinforced on that specific area.

Originally Posted by neilpride

.It emerged from the validation that some boats, particularly those with no girders had little hope of complying with this load case, without substantial local reinforcement..

It seems that after all the technical committee of RCD is paying attention regarding some keel losses and are demanding stronger boats in a mandatory way.

[neilpride]

Then tell me how are designed and build it those keel structures prior 2009 and even today... Ohh well your link say something like add to the basket, no way im going to pay for such a BS, sorry mate..

[Polux]

Originally Posted by neilpride

Then tell me how are designed and build it those keel structures prior 2009 and even today... Ohh well your link say something like add to the basket, no way im going to pay for such a BS, sorry mate..

Well, it is a long technical document (72 pages). I have it and you can have it too. If you don't want to pay what can I do? Anyway is way more technical and complex than that small validation study an the summary says what it is about:

ISO 12215-9:2011 defines the loads and specifies the scantlings of sailing craft appendages on monohull sailing craft with a length of hull of up to 24 m, measured according to ISO 8666. It gives design stresses, the structural components to be assessed, load cases and design loads for keel, centreboard and their attachments, computational methods and modelling guidance, and the means for compliance with its provisions.

Before it was regulated by:

ISO 12215-8:2009
Small craft -- Hull construction and scantlings -- Part 8: Rudders

[neilpride]

Obviously, if you want to build a keel grid structure strong enough to take a serious grounding without breaking the hull in pieces you need to get ridd off this Mickey mouse keel bolts washers troughbolted to the hull, Obviously the Jeaneau dont have a impresive hull ticknes , and obviously they are not troughbolted to a solid beam or stringer, and obviously those thin hollow grid liners dont do a proper job reinforcing the keel surrounding structure... just my 10 cents....

[neilpride]

Originally Posted by Polux

Well, it is a long technical document. I have it and you can have it too. If you don't want to pay what can I do? Anyway is way more technical and complex than that small validation study.

You can post it here, after all you pay for that...

[neilpride]

Hehehe, you know what, i strongly believe certain industry in the EU with the RCD ISO are just a bunch of rats covering his ass,, dont feel offended please...

[Polux]

Originally Posted by neilpride

You can post it here, after all you pay for that...

72 pages? do you want me to scan 72 pages and post them here? Don't you think that if you are professionally interested it would be far simpler to pay for that? After all they have made that with my tax money, it is just fair that you pay at least the work of having them available to all.

[neilpride]

Well ok ok, just post the part concerning keels structures, scantlings .. 72 pages is to much, you right!

[Polux]

Originally Posted by neilpride

Hehehe, you know what, i strongly believe certain industry in the EU with the RCD ISO are just a bunch of rats covering his ass,, dont feel offended please...

At least they seem to understand the documents, even the simple ones like the one you have posted. Why calling rats to European Naval Architects and Naval Engineers that are working to provide a higher degree of safety through mandatory rules that make boats stronger???? As you seem to have understood those evaluated boats would not have passed some of the rules and scantlings that are enforced now.

I don't fell offended it seem to me that it is you that lose all credibility when you call to highly knowledgeable technicians rats.

[smackdaddy]

Originally Posted by Zach

It's cold out side, and I've been enjoying red wine... Zach

You, sir, have my utmost respect.

[neilpride]

I dont mention NA or Designers, you do... But lets end this nosense discusión, you bring the point with that link, so you can post it or not , is up to you,.. peace!!!

[smackdaddy]

Originally Posted by neilpride

Obviously, if you want to build a keel grid structure strong enough to take a serious grounding without breaking the hull in pieces you need to get ridd off this Mickey mouse keel bolts washers troughbolted to the hull, Obviously the Jeaneau dont have a impresive hull ticknes , and obviously they are not troughbolted to a solid beam or stringer, and obviously those thin hollow grid liners dont do a proper job reinforcing the keel surrounding structure... just my 10 cents....

When you say things like "obviously" - it makes me think you didn't really read the report.

[Polux]

Originally Posted by smackdaddy

When you say things like "obviously" - it makes me think you didn't really read the report.

I think he read it but did not really understood it neither what it was about.